module/ice-9/save-stack.scm

   1 ;;; -*- mode: scheme; coding: utf-8; -*-
   2
   3 ;;;; Copyright (C) 1995,1996,1997,1998,1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010,2014
   4 ;;;; Free Software Foundation, Inc.
   5 ;;;;
   6 ;;;; This library is free software; you can redistribute it and/or
   7 ;;;; modify it under the terms of the GNU Lesser General Public
   8 ;;;; License as published by the Free Software Foundation; either
   9 ;;;; version 3 of the License, or (at your option) any later version.
  10 ;;;;
  11 ;;;; This library is distributed in the hope that it will be useful,
  12 ;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 ;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 ;;;; Lesser General Public License for more details.
  15 ;;;;
  16 ;;;; You should have received a copy of the GNU Lesser General Public
  17 ;;;; License along with this library; if not, write to the Free Software
  18 ;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19 ;;;;
  20
  21 \f
  22
  23 ;;; Commentary:
  24
  25 ;;; An older approack to debugging, in which the user installs a pre-unwind
  26 ;;; handler that saves the stack at the time of the error. The last stack can
  27 ;;; then be debugged later.
  28 ;;;
  29
  30 ;;; Code:
  31
  32 (define-module (ice-9 save-stack)
  33   ;; Replace deprecated root-module bindings, if present.
  34   #:export (stack-saved?
  35             the-last-stack
  36             save-stack))
  37
  38 ;; FIXME: stack-saved? is broken in the presence of threads.
  39 (define stack-saved? #f)
  40
  41 (define the-last-stack (make-fluid))
  42
  43 (define (save-stack . narrowing)
  44   (if (not stack-saved?)
  45       (begin
  46         (let ((stacks (fluid-ref %stacks)))
  47           (fluid-set! the-last-stack
  48                       ;; (make-stack obj inner outer inner outer ...)
  49                       ;;
  50                       ;; In this case, cut away the make-stack frame, the
  51                       ;; save-stack frame, and then narrow as specified by the
  52                       ;; user, delimited by the nearest start-stack invocation,
  53                       ;; if any.
  54                       (apply make-stack #t
  55                              2
  56                              (if (pair? stacks) (cdar stacks) 0)
  57                              narrowing)))
  58         (set! stack-saved? #t))))